So the first three are clearly C revisions and the last an A revision manufactured the year before. I don't know if the C is as usually expected a better core as most later revision IC but if these chips were becoming oriented to mainboard integration I wonder if they are the same cores of the previous B and A revisions or there might be (just asking myself) ipotethically a "power saving" version of it, I don't know what did change on these chip revisions.
I think I've found a Rev. C based card on those late low profile cheap cards and sounds like they were becoming oriented already to a low end market considering the competition back then. Also like the Riva 128 it's interesting to see few cards having the heatsink others not which might be cause a better chip revision didn't need it or some running at higher freqs who knows.
For Quake I hoped someone found some driver tweak or game engine tweak to make some of those game engine based titles running correctly, but I suppose only a driver upgrade would have solved that. It's interesting that beside the chip speed, slow cards like the Rage IIC based ones received drivers upgrade up the middle 1999 and most games even if slow are correctly accelerated as tested even Unreal Tournament, Half Life, Thief 1 and 2 games, 3DMark2000. Too bad many of these cards probably with some more driver upgrades would have improved a lot. The Rage Pro received drivers until the 2002. 😀